Rudder for skis



Dec. 6, 1966 MASAMI TOKUDA RUDDER FOR SKIS 5 Sheets-Sheet 1 Filed March 12, 1964 INVENTOR.

BY W m ATTYS.

c- 6, 1966 MASAMI TOKUDA 3,290,048

RUDDER FOR SKIS Filed March 12, 1964 5 Sheets-Sheet 2 ATTYS.

1966 MASAMl TOKUDA 3,290,048

RUDDER FOR SKIS Fil ed March 12, 1964 5 Sheets-Sheet s INVENTOR. mu' QZ M- Ham/m at We??? A rz'm United States Patent 3,290,048 RUDDER FOR SKIS Masami Tokuda, 56 Senjuhigashimachi, Adachi, Tokyo, Japan Filed Mar. 12, 1964, Ser. No. 351,896

Claims priority, application Japan, Mar. 18, 1963,

9 Claims. (Cl. 280-11.13)

The present invention relates to a rudder for skis, and more particularly to an automatic ski rudder.

Heretofore, snow skis have not been provided with rudders, and as a result, beginners have found it quite difficult to turn in the desired direction. The present invention provides a rudder arrangement with a two-fold purpose in mind: (1) to facilitate turning, and (2) to facilitate climbing snow-covered slopes.

To accomplish the first purpose, a novel rudder is placed on the under-side of the ski, enabling the skier to automatically change his direction with a reasonable degree of accuracy.

To accomplish the second purpose, the rudder is capable of rotation 90 degrees to the left or the right of the center line of the ski.

.The invention Will be set forth in greater detail in connection with the accompanying drawings wherein:

FIG. 1 is a. fragmentary inverted plan view illustrating the underside of a ski and showing the placement of a rudder in accordance with the present invention, wherein the rudder rotates approximately 45 degrees in each direction, as indicated in broken lines, as viewed from the line 11 in FIG. 2, with portions broken away;

FIG. 2 is a longitudinal sectional view taken along the lines 11-11 of FIG. 1;

FIG. 3 is a transverse sectional view taken along the irregular line III-III of FIG. 1;

FIG. 4 is a schematic representation showing the locations of the rear shaft when the distance between the main shaft andthe rear shaft is varied;

FIG. 5 is a fragmentary horizontal sectional view of a skihaving a modified rudder in accordance with this invention taken along the line V-V of FIG. 6, in which the guide slot for the rear shaft is straight;

FIG. 6 is a longitudinal section view taken along the line VIVI of FIG. 5;

FIG. 7 is a fragmentary view similar to FIG. 5 showing another rudder made in accordance with the present invention, taken along the line VIIVII in FIG. 8, in which the guide slot for the rear shaft is arcuate;

FIG. 8 is a longitudinal sectional view taken along the line VIIIVIII of FIG. 7;

FIG. 9a is a fragmentary sectional view taken along the line AA of FIG. 9b showing a ski embodying another rudder assembly in accordance with this invention which may be rotated 90 degrees;

FIG. 9b is an inverted horizontal sectional view taken along the line BB in FIG. 9a, in which the rudder is indicated in broken lines;

FIG. 90 is a view similar to FIG. 9b illustrating the position of the rudder as it rotates 45 degrees and the rear shaft is about to enter the climbing slot;

FIG. 9d is an exploded perspective view of the rudder assembly as it appears in FIGS. 9a and 9b, wherein the parts of the rudder assembly are about to be assembled;

FIG. 10 is a fragmentary inverted plan view of another rudder assembly wherein the rudder may be turned at right angles to the center line of the ski; and

FIG. 11 is a fragmentary view similar to FIG. 10 showing a further modified form of rudder assembly.

In all of the embodiments of the invention, the ski is provided on its underside with a base plate for mount- 3,290,048 Patented Dec. 6, 1966 ing a rudder for angular displacement in response to the application of a lateral force to the rudder. To this end,

the rudder is provided with a pair of upstanding shafts, the main shaft, which is at the forward end of the rudder, being mounted in a slot for displacement longitudinally of the ski, and the rear shaft being guided for lateral displacement as the main shaft is displaced. In each embodiment, the rudder is preferably free to turn at least 45 degrees to either side of the center line of the ski to facilitate turning, and in the embodiments of FIGS. 9 to 11 inclusive, the rudder may be turned a total of 90 degrees to each side of the center line to facilitate climbing.

In the embodiment of the invention illustrated in FIGS. 1 to 3, the base plate 1 is generally oval or egg-shaped, and has a tube 2 projecting upwardly in the rear of the base plate 1. The upper part of the tube 2 is threaded as indicated at 3, and the plate 1 is rigidly mounted on the ski 5 by a fastener in the form of a nut 4 engaging the threads 3. On the underside of the rear part of the base plate 1, a round hole rotatably mounts a disc 6 having a center shaft 7 passing up through the tube 2, and held in place by a washer 2a and a fastener 2b to prevent the disc 6 from falling away from the base plate 1.

The rudder 10 is a bar of an inverted generally triangular cross section, and has a shallow'round dished portion 9 on its front part.

A main shaft 11 projects perpendicularly from the upper side of the dished portion 9 and passes through a slot 8 which is disposed longitudinally of the ski, in the present instance, along the center line of the base plate 1, and

' is secured by a nut 12 on the top engaging over the upper side of the base plate 1, allowing movement of the shaft 11 along the slot but preventing drop-off.

A rear shaft 13 is screwed tothe upper side of the rudder 10 adjacent the main shaft 11 and is guided for lateral sliding movement. To this end, the upper part of the shaft 13 is engaged in a recess 14 at the edge of the disc 6, thereby moving the rudder 10 angularly by the rotation of the disc 6. The movement of the rudder is limited-by the main shaft 11 when the main shaft reaches the rearward terminal end of the slot 8. Thus,

the inclination of the rudder is always limited to within a constant angle to the center line of the base plate 1.

When skis are provided with rudders afiixed to the underside of the ski, the rudder embeds itself into the snow, forcing the ski to go straight along its center line.

The rudder turns naturally to the direction of least resistance and the main shaft 11 travels to the forward terminal end of the slot 8. The rear shaft 13 then automatically comes on the center line of the plate 1, and the rudder aligns the center line of the ski, not disturbing the skiing direction.

When it is desired to turn to the right, the right ski is shifted to the right, whereby the snow pressure is then exerted laterally upon the right side of the rudder, and both shafts 11 and 13 are moved to the rear, the disc being forced to turn clockwise to position the rudder as indicated in broken lines at 10a in FIG. 1. When the rudder reaches the limit position, the shafts 11 and 13 come to rest in the rear-most positions indicated at 11a and 1311. Then the rudder assumes a determined angle, causing the ski to automatically turn.

When it is desired to assume a straight line after turning, the weight of the skier must be shifted to the center of the right side of the ski. Because of the increasing resistance on the left side of the rudder, the rudder is forced to automatically align with the center line of the ski. As the shafts 11 and 13 are displaced forwardly and to the right respectively, the rudder moves to the original position on the center line.

By modifying the rudder and the base plate, the disshaft is changed, the movement of the rear shaft is varied' corresponding to the position of the main shaft as indi cated in FIG. 4. When the distance between the shafts is very close, as indicated at 11 and 13, the movement of the shaft to the position 13a is represented by an are a, and when the distance is greater as indicated at 11 and 130, the movement then becomes a straight line c, and when the distance is even greater, as indicated at 11 and 13] and 13g, the movement becomes convex, but the movement of the shaft 13 need not always be curved or straight.

In the embodiment shown in FIGS. 5 and 6, the ski 50 has a modified base plate which is secured to the ski by a nut and which includes an axial slot 80 mounting the main shaft for longitudinal movement between the full line position shown at 11c and the broken line position shown at 11b. The rear shaft 130 is guided for lateral movement upon longitudinal movement of the rudder 100. To this end, a guide slot 15 is provided on the base plate 1c, instead of usilizing the disc of the previous embodiment.

In the embodiment shown in FIGS. 7 and 8, the ski 5d has a modified base plate 1d which is secured thereto by a fastener 2d and includes an axial slot 8d which mounts the main shaft 11d for longitudinal movement. The rear shaft 13a is guided for lateral movement upon longitudinal movement of the rudder 10d. To this end, an arcuate guide slot 16 is provided on the base plate Id. In these cases, the rounded portions 9c and 9d of the rudders 10c and 10d respectively may be made a little larger to prevent the snow from getting directly into the slots 15 and 16. The actions and effects of these embodiments are similar to those explained above. Both ends of the slots 15 and 16 are safety rest points for the rear shaft of the rudder.

Another improved version of the rudder which allows further angular motion than that in the above examples, is illustrated in FIGS. 9a through 9d. In the previous embodiment, the movement of the rudder is limited to a definite angle, preferably 45 degrees, by the eccentricity of the rear shaft and the distance between the main and rear shafts. In the embodiment of FIGS. 9a through 9d, a ski 5x has a base plate 1x secuerd thereto by a tube 2x and fastener 4x. A rudder 10x is mounted on the plate 1x by upstanding shafts 11x and13x. The shaft 11x is slidable in an axial slot 8x and is held against drop-off by a fastener 12x. The shaft 13x engages in a recess 14x in a circular disc 6x mounted for rotation in a circular hole in the base plate 1x by means of an upstanding shaft and fastener 7x. An enlarged dished portion 9x is provided at the forward end of the rudder 10x. In this embodiment of the invention, the recess 14x is opened to the outer periphery of the disc 6x in a radial direction,

and detents 15x and 16x are provided in the periphery of the disc 6x on opposite sides of the recess 14x to align with the axial slot 8x and form the rearward terminus thereof when the disc 6x is rotated to position the rudder 10x at the 45 degree position. Climbing slots 17 and 18 intersect the opening for the disc 6x in the base plate 1x at a point in registry with the recess 14x when the rudder 10x is in the latter position. The slots 17 and 18 are arcuate and have a radius of curvature corresponding to the spacing between the shafts 11x and 13x. The center of curvature of both arcuate slots coincides with center of the main shaft 11x when it is displaced to the rearward end of the axial slot 8x.

Therefore, when the main shaft 11x is displaced to its rearward limit position in the detent aligned with the slot 8x, and the shaft 13x is laterally displaced to the position 13x in FIG. 9c, the rudder 10x is rotated to the position 10x, enabling the shaft 13x to disengage itself from the recess 14x and enter the climbing slot 18 and rotate 4 degree-sto the position 13x" at the forward end of the climbing slot 18. With the rudder in the 90 degree position shown at 10x", the ski' may skid laterally but the rudder prevents the ski from skidding backwards when ascending snow-covered slopes. The engagement of the main shaft 11x in the detent 15x prevents the disc 6x from rotating so that the rudder may return from the position 10x" to the position 10x, and the shaft 13x may engage in the recess 14x.

The same character of motion of the rudder may be accomplished without the complication of the engagement of the disc 6x and the rear shaft 13x. For example, in the embodiments of FIGS. 10 and 11, the rear shaft is guided for lateral movement in fixed slots of the base plate. In the embodiment of FIG. 10, the base plate 1y serves to mount the rudder 10y for angular movement to the positions indicated at 10y and 10y". To this end, the main shaftlly of the rudder 10y is engaged in an axial slot 8y of the base plate. The rear shaft 13y is guided by a transverse slot 16y having a length sufficient to enable angular displacement of the rudder 10y to the position 10y. Climbing slots 17y and 18y intersect the arcuate transverse slot 16y by its outer ends, and have a radius of curvature corresponding to the spacing between the shafts 11y and 13y and a center of curvature coinciding with the center of the shaft 11y when it is in its rearward limit position. In this manner, the rudder 10 may rotate to the 90 degree position by displacement of the shaft 13y in the climbing slot 17y.

A similar arrangement is shown in FIG. 11 wherein the base plate 1z mounts the rudder 10z by means of the main shaft 112 and rear shaft 13z engaging respectively in an axial slot 8z and a transverse slot 152. In this embodiment of the invention, the transverse slot 151 is angular in form and extends outwardly from the center line a distance to permit the rudder 101 to assume a 45 degree angular position as indicated at 102'. Climbing slots 172 and 18z intersect the angular slot 152 at its outer terminal ends, the slots 171 and 18z being arcuate with a center of curvature coinciding with the position of the shaft 11z when it is in its rearward limit position. It is apparent that the rudder 102 operates in a manner similar to the embodiment-s of FIGS. 9 and 10 respectively.

It may be convenient to provide a spring or magnet adjacent the forward terminal end of the arcuate climbing slots to hold the rudder perpendicular to the center line of the ski and prevent the rudder from swinging freely during slope climbing.

Furthermore, if a small detent is made in the middle of the transverse slot, as shown at 19 in the slot 15a in FIG. 11, the rear shaft of the rudder may rest in the detent, placing the rudder in line with the center line of the ski.

It is apparent, therefore, that the present invention provides a rudder assembly which enables beginning skiers to turn easily, and when the mechanism is con structed as shown in FIGS. 9 to 11 inclusive, the rudder may be used not only for turning but also to prevent slipping when climbing slopes.

Various changes in the size, shape, and arrangement of the various parts of the invention may be made without departing from the spirit of the invention, within the scope of the appended claims:

1. A rudder for a ski comprising a base plate adapted to be rigidly mounted on the underside of the ski, an elongated slot in said plate disposed axially of said ski, a rudder mounted on said plate to depend therebelow and normally disposed with its centerline axial of said ski, a main shaft projected upwardly from said rudder adjacent its forward end and slidable longitudinally in said slot upon longitudinal displacement of said rudder, a rear shaft projecting upwardly from said rudder, and guide means slidably mounting said rear shaft for lateral displacement in said base plate, whereby upon application of a lateral force against said rudder said rear shaft is displaced laterally effecting displacement of said rudder both angularly about said main shaft and longitudinally within said slot.

2. A rudder according to claim 1 wherein said guide means comprises a disc having a pivotal center mounted in said plate for rotary movement about said center, a recess in said disc oifset from said center and slidably mounting said rear shaft whereby rotary movement ofsaid disc effects said lateral displacement of the rear shaft.

3. A rudder according to claim 2 wherein said disc is circular and said plate has a circular opening for mounting said disc for rotation about its center, said recess being open radially to the periphery of said disc, and at least one arcuate slot intersecting said opening operable to slidably receive said rear shaft upon further lateral displacement of said rudder, the center of curvature of said arcuate slot coinciding with the center of said main shaft when it is displaced to the rearward end of said axial slot.

4. A rudder according to claim 3 wherein said axial slot terminates within said circular opening, said disc including a detent operable, when said recess is in registry with said arcuate slot, to align with said axial slot and to constitute the rearward end thereof, said main shaft seating in said detent to anchor said disc against inadvertent rotation.

5. A rudder according to claim 1 wherein said guide means comprises a transverse slot in said base plate mounting said rear shaft for slidable displacement transversely of said ski upon longitudinal displacement of said main shaft in said axial slot.

6. A rudder according to claim 5 wherein said axial slot is disposed along the centerline of the ski and said transverse slot intersects the centerline at a point spaced rearwardly from the forward terminus of said axial slot a distance equal to the spacing between said shafts, said transverse slot extending outwardly from the centerline of theski at each side a distance whereby said rudder is free to turn degrees upon displacement of said main shaft to said rearward terminal end.

7. A rudder according to claim 6 wherein said base plate includes an arcuate slot at each end of said transverse slot extending forwardly in line with the rearward terminal end of said axial slot with a center of curvature coincident with the rearward terminal end of said axial slot and a radius of curvature equal to the spacing between said shafts whereby the rudder may pivot on said main shaft when it is at the rearward end of said slot to a position perpendicular to the centerline of the ski.

8. A rudder according to claim 7 wherein said transverse slot and said arcuate slots merge at a substantial angle to provide a rest point for said rear shaft when said rudder is positioned at 45 degrees to the centerline.

9. A rudder according to claim 6 including a detent in said transverse slot at its intersection with said centerline to provide a rest point for said rear shaft when said rudder is aligned with said centerline.

References Cited by the Examiner UNITED STATES PATENTS 2,241,733 5/1941 Perry 28021 3,027,576 4/1962 Fines 9310 FOREIGN PATENTS 194,765 1/1958 Austria.

BENJAMIN HERSH, Primary Examiner.

MILTON L. SMITH Examiner 

1. A RUDDER FOR A SKI COMPRISING A BASE PLATE ADAPTED TO BE RIGIDLY MOUNTED ON THE UNDERSIDE OF THE SKI, AN ELONGATED SLOT IN SAID PLATE DISPOSED AXIALLY OF SAID SKI, A RUDDER MOUNTED ON SAID PLATE TO DEPEND THEREBELOW AND NORMALLY DISPOSED WITH ITS CENTERLINE AXIAL OF SAID SKI, A MAIN SHAFT PROJECTED UPWARDLY FROM SAID RUDDER ADJACENT ITS FORWARD END AND SLIDABLE LONGITUDINALLY IN SAID SLOT UPON LONGITUDINAL DISPLACEMENT OF SAID RUDDER, A REAR SHAFT PROJECTING UPWSARDLY FROM SAID RUDDER, AND GUIDE MEANS SLIDABLY MOUNTING SAID REAR SHAFT FOR LATERAL DISPLACEMENT IN SAID BASE PLATE, WHEREBY UPON APPLICATION OF A LATERAL FORCE AGAINST SAID RUDDER SAID REAR SHAFT IS DISPLACED LATERALLY EFFECTING DISPLACEMENT OF SAID RUDDER BOTH ANGULARLY ABOUT SAID MAIN SHAFT AND LONGITUDINALLY WITHIN SAID SLOT. 